[PATCH v2] qga: Correct loop count in qmp_guest_get_vcpus()

[Lin Ma]

The guest-get-vcpus returns incorrect vcpu info in case we hotunplug vcpus(not
the last one).
e.g.:
A VM has 4 VCPUs: cpu0 + 3 hotunpluggable online vcpus(cpu1, cpu2 and cpu3).
Hotunplug cpu2,  Now only cpu0, cpu1 and cpu3 are present & online.

./qmp-shell /tmp/qmp-monitor.sock
(QEMU) query-hotpluggable-cpus
{"return": [
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu2", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
 "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
]}

(QEMU) device_del id=cpu2
{"return": {}}

(QEMU) query-hotpluggable-cpus
{"return": [
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
 "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
 "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
]}

Before:
./qmp-shell -N /tmp/qmp-ga.sock
Welcome to the QMP low-level shell!
Connected
(QEMU) guest-get-vcpus
{"return": [
{"online": true, "can-offline": false, "logical-id": 0},
{"online": true, "can-offline": true, "logical-id": 1}]}

After:
./qmp-shell -N /tmp/qmp-ga.sock
Welcome to the QMP low-level shell!
Connected
(QEMU) guest-get-vcpus
{"return": [
{"online": true, "can-offline": false, "logical-id": 0},
{"online": true, "can-offline": true, "logical-id": 1},
{"online": true, "can-offline": true, "logical-id": 3}]}

Signed-off-by: Lin Ma <lma@suse.com>
---
 qga/commands-posix.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index c089e38120..d37525b5a3 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -2467,6 +2467,7 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error 
**errp)
     int64_t current;
     GuestLogicalProcessorList *head, **link;
     long sc_max;
+    int i = 0;
     Error *local_err = NULL;
 
     current = 0;
@@ -2474,7 +2475,7 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error 
**errp)
     link = &head;
     sc_max = SYSCONF_EXACT(_SC_NPROCESSORS_CONF, &local_err);
 
-    while (local_err == NULL && current < sc_max) {
+    while (local_err == NULL && i < sc_max) {
         GuestLogicalProcessor *vcpu;
         GuestLogicalProcessorList *entry;
         int64_t id = current++;
@@ -2482,6 +2483,7 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error 
**errp)
                                      id);
 
         if (g_file_test(path, G_FILE_TEST_EXISTS)) {
+            i++;
             vcpu = g_malloc0(sizeof *vcpu);
             vcpu->logical_id = id;
             vcpu->has_can_offline = true; /* lolspeak ftw */
-- 
2.26.0